1. Field of the Invention
The present invention relates to a system and an apparatus for compressing and expanding data, and more particularly to a system and an apparatus for compressing data, transferring the compressed data, and expanding the compressed data into original data.
2. Description of the Related Art
Heretofore, apparatus which exchange data therebetween often incorporate a system for compressing data, transferring the compressed data, and expanding the compressed data into original data in order to reduce the memory size which stores data to be transferred, reduce the amount of data to be transferred, and shorten the period of time required to transfer data.
FIG. 1 of the accompanying drawings shows a conventional data compressing and expanding system for transferring data between two apparatus 110a, 110b. The apparatus 110a, 110b have respective compressing units 111a, 111b for compressing data to be transferred, and respective expanding units 112a, 112b for expanding compressed data that have been transferred. The conventional data compressing and expanding system includes a storage 120 connected between the apparatus 110a, 110b for temporarily storing transferred data. While data is shown as being transferred between the two apparatus in the conventional data compressing and expanding system, data may be transferred between a plurality of apparatus.
Data processing operation of the conventional data compressing and expanding system will be described below with reference to FIGS. 1 and 2 of the accompanying drawings. It is assumed that data will be transferred from the apparatus 110a to the apparatus 110b.
First, a string of byte data to be transferred is compressed into a compressed string of byte data by a compression processor or compression software in the compressing unit 111a.
The compressed string of byte data is sent from the compressing unit 111a to the storage 120, and temporarily stored in the storage 120.
Thereafter, the stored compressed string of byte data is read out of the storage 120, and transferred to the apparatus 110b. The compressed string of byte data may not be stored in the storage 120, but may be transferred directly to the apparatus 110b.
The compressed string of byte data which has been transferred to the apparatus 110b is expanded by an expansion processor or expansion software in the expanding unit 112b, thereby recovering the uncompressed string of byte data.
Most of the time required for the conventional data compressing and expanding system to transfer data is spent by compressing and expanding the data. There are limitations on efforts to reduce the time needed to compress and expand data. Since it is difficult to shorten the time required to transfer data, the time required to transfer data tends to increase if the amount of data to be transferred increases.